The present invention relates to a method for correcting an actuator characteristic of a clutch actuator for a friction clutch of a vehicle transmission.
Modern vehicle transmissions, such as automated manual transmissions, dual clutch transmissions and automatic torque converter transmissions, have friction clutches actuated in an automated manner. For example, dual clutch transmissions have two friction clutches, which are each assigned to a transmission section and can be actuated in an overlapping manner in order to be able to carry out a gear change without interrupting the traction. In this case, the friction clutches are actuated by respective clutch actuators, which can be designed as electric or hydraulic actuators.
The friction clutch is controlled, for example, via the clutch pressure. As a rule, however, the clutch actuator is activated via another variable, such as, for example, the electric current which is required for activating an electronic pressure control valve or an electromotive or electromagnetic actuator.
In the production of such vehicle transmissions, a vehicle-specific teach-in is carried out at the end, and this teach-in relates a first desired variable, such as a desired clutch pressure, to a second desired variable, such as a desired actuator current. In the process, the entire operating range is scanned step by step and then completed iteratively.
During operation, changes in the clutch actuator, for example changes in a hydraulic circuit for actuating the friction clutch, are estimated. However, this estimation is often inaccurate.